A combustor of a gas turbine includes a transition piece that defines a passage for combustion gas, and a fuel supply unit that supplies fuel along with air into this transition piece. Inside the transition piece, the fuel is combusted and combustion gas generated by the combustion of the fuel flows. Thus, an inner surface of the transition piece is exposed to ultrahigh-temperature combustion gas.
Therefore, the combustor disclosed in Patent Literature 1, for example, has a plurality of cooling channels formed between air inner surface and an outer surface of a combustion liner that defines a passage for combustion gas. Compressed air present outside the combustion liner flows as a cooling medium through these cooling channels.